<?php
//dezend by http://www.yunlu99.com/ QQ:270656184
defined('BASEPATH') || exit('No direct script access allowed');
class CI_DB_postgre_forge extends CI_DB_forge
{
	/**
	 * UNSIGNED support
	 *
	 * @var	array
	 */
	protected $_unsigned = array('INT2' => 'INTEGER', 'SMALLINT' => 'INTEGER', 'INT' => 'BIGINT', 'INT4' => 'BIGINT', 'INTEGER' => 'BIGINT', 'INT8' => 'NUMERIC', 'BIGINT' => 'NUMERIC', 'REAL' => 'DOUBLE PRECISION', 'FLOAT' => 'DOUBLE PRECISION');
	/**
	 * NULL value representation in CREATE/ALTER TABLE statements
	 *
	 * @var	string
	 */
	protected $_null = 'NULL';

	public function __construct(&$db)
	{
		parent::__construct($db);

		if (version_compare($this->db->version(), '9.0', '>')) {
			$this->create_table_if = 'CREATE TABLE IF NOT EXISTS';
		}
	}

	protected function _alter_table($alter_type, $table, $field)
	{
		if (in_array($alter_type, array('DROP', 'ADD'), true)) {
			return parent::_alter_table($alter_type, $table, $field);
		}

		$sql = 'ALTER TABLE ' . $this->db->escape_identifiers($table);
		$sqls = array();
		$i = 0;

		for ($c = count($field); $i < $c; $i++) {
			if ($field[$i]['_literal'] !== false) {
				return false;
			}

			if (version_compare($this->db->version(), '8', '>=') && isset($field[$i]['type'])) {
				$sqls[] = $sql . ' ALTER COLUMN ' . $this->db->escape_identifiers($field[$i]['name']) . ' TYPE ' . $field[$i]['type'] . $field[$i]['length'];
			}

			if (!empty($field[$i]['default'])) {
				$sqls[] = $sql . ' ALTER COLUMN ' . $this->db->escape_identifiers($field[$i]['name']) . ' SET DEFAULT ' . $field[$i]['default'];
			}

			if (isset($field[$i]['null'])) {
				$sqls[] = $sql . ' ALTER COLUMN ' . $this->db->escape_identifiers($field[$i]['name']) . ($field[$i]['null'] === true ? ' DROP NOT NULL' : ' SET NOT NULL');
			}

			if (!empty($field[$i]['new_name'])) {
				$sqls[] = $sql . ' RENAME COLUMN ' . $this->db->escape_identifiers($field[$i]['name']) . ' TO ' . $this->db->escape_identifiers($field[$i]['new_name']);
			}

			if (!empty($field[$i]['comment'])) {
				$sqls[] = 'COMMENT ON COLUMN ' . $this->db->escape_identifiers($table) . '.' . $this->db->escape_identifiers($field[$i]['name']) . ' IS ' . $field[$i]['comment'];
			}
		}

		return $sqls;
	}

	protected function _attr_type(&$attributes)
	{
		if (isset($attributes['CONSTRAINT']) && (stripos($attributes['TYPE'], 'int') !== false)) {
			$attributes['CONSTRAINT'] = NULL;
		}

		switch (strtoupper($attributes['TYPE'])) {
		case 'TINYINT':
			$attributes['TYPE'] = 'SMALLINT';
			$attributes['UNSIGNED'] = false;
			return NULL;
		case 'MEDIUMINT':
			$attributes['TYPE'] = 'INTEGER';
			$attributes['UNSIGNED'] = false;
			return NULL;
		default:
			return NULL;
		}
	}

	protected function _attr_auto_increment(&$attributes, &$field)
	{
		if (!empty($attributes['AUTO_INCREMENT']) && ($attributes['AUTO_INCREMENT'] === true)) {
			$field['type'] = $field['type'] === 'NUMERIC' ? 'BIGSERIAL' : 'SERIAL';
		}
	}
}

?>
